Scientists Reach Milestone In Quest For Smart Windows

Smart windows change how much sunlight they let through on a hot day. Such windows could reduce the demand for energy by reducing the need for air conditioning. This quest has been going on for years but it's got years to go before the project becomes a reality.

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Not that I know this from any personal experience, but getting an invention to work right does not happen overnight. It can actually take years of trial and error. It's time for Joe's Big Idea, our series exploring the minds and motivations of scientists and inventors. Today, NPR's Joe Palca has the story of an energy saving device called a Smart Window that's being developed at a Department of Energy lab in California.

JOE PALCA, BYLINE: At the Lawrence Berkeley Laboratory in California, Delia Milliron and her colleagues have been making microscopic crystals called nanocrystals out of indium and tin. As they report in today's issue of the journal Nature, when you impregnate a special glass with these nanocrystals, you get a window that can block either the warming rays from the sun or the light rays from the sun, or both.

Normally, a paper in Nature spells the end of a project. Not so with Milliron's quest to bring smart windows to the consumer. This project has been going on for years and it's got years to go. What's more, NPR has been reporting on this project for a while. Here's Milliron talking to NPR in 2011.

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DELIA MILLIRON: This is Wanda, our robot that makes nanocrystals.

PALCA: Milliron made Wanda so it could assemble and test different ingredients for making her nanocrystals. And here's Milliron talking to me colleague Richard Harris in March of this year.

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MILLIRON: Wanda's big brother Herman is on the way.

PALCA: Herman is a faster more sophisticated robot that can make and test nanocrystals faster than Wanda. Milliron needs Herman because she needs to make her nanocrystal out of cheaper materials.

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MILLIRON: The element that pops up near the top of our price list at the moment that we worry about is the Indium used in our Indium tin oxide nanocrystals.

PALCA: Indium costs about $250 a pound. Milliron is going to have to find cheaper ingredients if she wants to make her smart windows cost competitive. And even if she can do that, there's still the matter of scale-up. Making a window in a lab is one thing. Manufacturing tens of thousands of windows is another. So how long will it be before these windows start appearing in buildings or homes?

Well, that's a tough question to answer. When Milliron and her colleagues first started talking about their smart windows a year and a half ago, they thought the answer would be three years. Expectations hadn't changed when Milliron told Richard Harris earlier this year.

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MILLIRON: In terms of demonstration products, I think it would be reasonable to see something even in the next three years or so.

PALCA: And when I talked to her last week, she said there was progress but still a ways to go.

MILLIRON: We're discussing with very large scale glass manufacturers what really needs to happen to make it viable for broad deployment in architectural glass.

PALCA: The point here is that getting a good idea out of the lab and into the show room requires patience, hard work, and yeah, maybe even a bit of luck. When Milliron talked to Richard, she spelled out for him the hurdles that lie ahead: finding the right materials, scaling up the manufacturing process, making glass that's free from defects.

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RICHARD HARRIS, BYLINE: But you feel that's all handleable?

MILLIRON: I think so. I mean I'm an optimist. I think you actually can't be a good scientist without being a bit of an optimist. Because frankly, most cool ideas don't work. Or at least they don't work initially. And you have to get up the next day and be very enthusiastic again and believe it's going to work and keep trying, and only in that way do we make any progress on science.

PALCA: I'll check back with Milliron in a couple of years or so and let you know how she's doing. Joe Palca, NPR News.

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